Oxygenated Triazine-Heptazine Heterostructure Creates an Enormous Ascension to the Visible Light Photocatalytic Hydrogen Evolution Performance of Porous C3N4 Nanosheets

A highly efficient g-C₃N₄ photocatalyst is developed by a novel one-pot thermal polymerization method under a salt fog environment generated by heating the aqueous solution of urea and mixed metal salts of NaCl/KCl, namely SF-CN. Thanks to the synergistic effect of the oxygenation and chemical etching of the salt fog, the obtained SF-CN is an oxygenated ultrathin porous carbon nitride with an intermolecular triazine-heptazine heterostructure, meanwhile, shows enlarged specific surface area, greatly enhanced absorption of visible light, narrowed band gap with a lower conduction band, and an increased photocurrent response due to the effective separation of photogenerated holes and electrons, comparing to those of pristine g-C₃N₄. The theoretical simulations further reveal that the triazine-heptazine heterostructure possesses better photocatalytic hydrogen evolution (PHE) capability than pure triazine and heptazine carbon nitrides. In turn, SF-CN demonstrates an excellent visible light PHE rate of 18.13 mmol h⁻¹ g⁻¹, up to 259.00 times of that of pristine g-C₃N₄.     

The Collision between g-C3N4 and QDs in the Fields of Energy and Environment: Synergistic Effects for Efficient Photocatalysis

Recently, graphitic carbon nitride (g-C₃N₄) has attracted increasing interest due to its visible light absorption, suitable energy band structure, and excellent stability. However, low specific surface area, finite visible light response range (<460 nm), and rapid photogenerated electron–hole (e⁻–h⁺) pairs recombination of the pristine g-C₃N₄ limit its practical applications. The small size of quantum dots (QDs) endows the properties of abundant active sites, wide absorption spectrum, and adjustable bandgap, but inevitable aggregation. Studies have confirmed that the integration of g-C₃N₄ and QDs not only overcomes these limitations of individual component, but also successfully inherits each advantage. Encouraged by these advantages, the synthetic strategies and the fundamental of QDs/g-C₃N₄ composites are briefly elaborated in this review. Particularly, the synergistic effects of QDs/g-C₃N₄ composites are analyzed comprehensively, including the enhancement of the photocatalytic performance and the avoidance of aggregation. Then, the photocatalytic applications of QDs/g-C₃N₄ composites in the fields of environment and energy are described and further combined with DFT calculation to further reveal the reaction mechanisms. Moreover, the stability and reusability of QDs/g-C₃N₄ composites are analyzed. Finally, the future development of these composites and the solution of existing problems are prospected.     

Construction of hybrid g-C3N4/CdO nanocomposite with improved photodegradation activity of RhB dye under visible light irradiation

The hybrid graphitic carbon nitride-cadmium oxide (g-C₃N₄/CdO) nanocomposite was fabricated using chemical precipitation and self-assembly method. The photocatalysts were characterised by XRD, XPS, FTIR, BET, TEM, FESEM, UV-Vis and PL spectroscopy. Based on the optical study, visible light harvesting was improved and the band gap of bulk g-C₃N₄ to hybrid g-C₃N₄/CdO nanocomposite was greatly reduced from 2.72 eV to 2.35 eV, signifying a better charge carrier mobility. The photocatalytic activity were further assessed by conducting rhodamine B (RhB) photodegradation reaction using visible light. An excellent dye removal efficiency of 96% was achieved when 1.5 g/L of hybrid g-C₃N₄/CdO nanocomposite was used with an initial concentration of 10 ppm for 120 min whereas only 66% of RhB was removed by bulk g-C₃N₄ within the same operating conditions. Besides, reusability tests were carried out and evidenced that hybrid g-C₃N₄/CdO nanocomposite can be recycled up to four times by retaining the degradation efficiency. The scavenging studies confirmed that the RhB photodegradation using hybrid g-C₃N₄/CdO nanocomposite was controlled by valance band h⁺ and O²⁻ oxidation reactions. Conclusively, the inclusion of CdO onto g-C₃N₄ resulted in remarkable photocatalytic activity for dye degradation applications.     

Constructing Ru@C3N4/Cu Tandem Electrocatalyst with Dual-Active Sites for Enhanced Nitrate Electroreduction to Ammonia

Electroreduction of nitrate to ammonia reaction (NO₃⁻RR) is considered as a promising carbon-free energy technique, which can eliminate nitrate from waste-water also produce value-added ammonia. However, it remains a challenge for achieving satisfied ammonia selectivity and Faraday efficiency (FE) due to the complex multiple-electron reduction process. Herein, a novel Tandem electrocatalyst that Ru dispersed on the porous graphitized C₃N₄ (g-C₃N₄) encapsulated with self-supported Cu nanowires (denoted as Ru@C₃N₄/Cu) for NO₃⁻RR is presented. As expected, a high ammonia yield of 0.249 mmol h⁻¹ cm⁻² at −0.9 V and high FE_NH3 of 91.3% at −0.8 V versus RHE can be obtained, while achieving excellent nitrate conversion (96.1%) and ammonia selectivity (91.4%) in neutral solution. In addition, density functional theory (DFT) calculations further demonstrate that the superior NO₃⁻RR performance is mainly resulted from the synergistic effect between the Ru and Cu dual-active sites, which can significantly enhance the adsorption of NO₃⁻ and facilitate hydrogenation, as well as suppress the hydrogen evolution reaction, thus lead to highly improved NO₃⁻RR performances. This novel design strategy would pave a feasible avenue for the development of advanced NO₃⁻RR electrocatalysts.     

Super-Photothermal Effect-Mediated Fast Reaction Kinetic in S-Scheme Organic/Inorganic Heterojunction Hollow Spheres Toward Optimized Photocatalytic Performance

Using full solar spectrum for energy conversion and environmental remediation is a major challenge, and solar-driven photothermal chemistry is a promising route to achieve this goal. Herein, this work reports a photothermal nano-constrained reactor based on hollow structured g-C₃N₄@ZnIn₂S₄ core–shell S-scheme heterojunction, where the synergistic effect of super-photothermal effect and S-scheme heterostructure significantly improve the photocatalytic performance of g-C₃N₄. The formation mechanism of g-C₃N₄@ZnIn₂S₄ is predicted in advance by theoretical calculations and advanced techniques, and the super-photothermal effect of g-C₃N₄@ZnIn₂S₄ and its contribution to the near-field chemical reaction is confirmed by numerical simulations and infrared thermography. Consequently, the photocatalytic degradation rate of g-C₃N₄@ZnIn₂S₄ for tetracycline hydrochloride is 99.3%, and the photocatalytic hydrogen production is up to 4075.65 µmol h⁻¹ g⁻¹, which are 6.94 and 30.87 times those of pure g-C₃N₄, respectively. The combination of S-scheme heterojunction and thermal synergism provides a promising insight for the design of an efficient photocatalytic reaction platform.     

Promoting CO2 Dynamic Activation via Micro-Engineering Technology for Enhancing Electrochemical CO2 Reduction

Optimizing the coordination structure and microscopic reaction environment of isolated metal sites is promising for boosting catalytic activity for electrocatalytic CO₂ reduction reaction (CO₂RR) but is still challenging to achieve. Herein, a newly electrostatic induced self-assembly strategy for encapsulating isolated Ni-C₃N₁ moiety into hollow nano-reactor as I-Ni SA/NHCRs is developed, which achieves FE_CO of 94.91% at −0.80 V, the CO partial current density of ≈−15.35 mA cm⁻², superior to that with outer Ni-C₂N₂ moiety (94.47%, ≈−12.06 mA cm⁻²), or without hollow structure (92.30%, ≈−5.39 mA cm⁻²), and high FE_CO of ≈98.41% at 100 mA cm⁻² in flow cell. COMSOL multiphysics finite-element method and density functional theory (DFT) calculation illustrate that the excellent activity for I-Ni SA/NHCRs should be attributed to the structure-enhanced kinetics process caused by its hollow nano-reactor structure and unique Ni-C₃N₁ moiety, which can enrich electron on Ni sites and positively shift d-band center to the Fermi level to accelerate the adsorption and activation of CO₂ molecule and *COOH formation. Meanwhile, this strategy also successfully steers the design of encapsulating isolated iron and cobalt sites into nano-reactor, while I-Ni SA/NHCRs-based zinc-CO₂ battery assembled with a peak power density of 2.54 mW cm−⁻² is achieved.     

Regulating the Electronic Structure of Bismuth Nanosheets by Titanium Doping to Boost CO2 Electroreduction and Zn–CO2 Batteries

The electrochemical carbon dioxide reduction reaction (E-CO₂RR) to formate is a promising strategy for mitigating greenhouse gas emissions and addressing the global energy crisis. Developing low-cost and environmentally friendly electrocatalysts with high selectivity and industrial current densities for formate production is an ideal but challenging goal in the field of electrocatalysis. Herein, novel titanium-doped bismuth nanosheets (Ti Bi NSs) with enhanced E-CO₂RR performance are synthesized through one-step electrochemical reduction of bismuth titanate (Bi₄Ti₃O₁₂). We comprehensively evaluated Ti Bi NSs using in situ Raman spectra, finite element method, and density functional theory. The results indicate that the ultrathin nanosheet structure of Ti Bi NSs can accelerate mass transfer, while the electron-rich properties can accelerate the production of *CO₂⁻ and enhance the adsorption strength of *OCHO intermediate. The Ti Bi NSs deliver a high formate Faradaic efficiency (FE_formate) of 96.3% and a formate production rate of 4032 µmol h⁻¹ cm⁻² at −1.01 V versus RHE. An ultra-high current density of −338.3 mA cm⁻² is achieved at −1.25 versus RHE, and simultaneously FE_formate still reaches more than 90%. Furthermore, the rechargeable Zn–CO₂ battery using Ti Bi NSs as a cathode catalyst achieves a maximum power density of 1.05 mW cm⁻² and excellent charging/discharging stability of 27 h.     

In-situ synthesized and photocatalytic performance evaluation of MoS2-C-g-C3N4 heterostructure photocatalyts

The heterostructure between two semiconductor materials that had suitable band edge positions can contribute to the separation of photoelectrons and holes. In this paper, the heterostructure MoS₂-C-g-C₃N₄ photocatalysts were in-situ synthesized at one-pot high temperature processing. The obtained 0.4 MoS₂-C-g-C₃N₄ composites displayed the highest photocatalytic hydrogen evolution activity with a corresponding H₂ evolution rate of 238 μmol g⁻¹h⁻¹, which was about 4.5 times higher than that of 3% C-g-C₃N₄, and the photocatalyts exhibited excellent stability which was used for photocatalytic hydrogen evolution reaction for 12 h. The 0.4 MoS₂-C-g-C₃N₄ sample displayed well degradation activities for MO, MB, RhB, MR and Ar18, and the scavenging studies indicated the major involvement of ·O₂^– radicals in the degradation process. The enhanced photocatalytic activity of MoS₂-C-g-C₃N₄ composite was predominantly attributed to the synergistic effects of type II heterostructure between g-C₃N₄ and MoS₂, which effectively accelerated the transfer and separation of photogenerated charge carriers. Besides, the introduction of noble metal-free MoS₂ co-catalyst further improved visible light absorption and provided more active sites for H₂ evolution reaction. Such work is promising for designing a novel heterostructure photocatalysts for solar-to-fuel conversion and environmental modification.     

In Situ Constructed Perovskite–Chalcogenide Heterojunction for Photocatalytic CO2 Reduction

Perovskite nanocrystals (PNCs) are promising candidates for solar-to-fuel conversions yet exhibit low photocatalytic activities mainly due to serious recombination of photogenerated charge carriers. Constructing heterojunction is regarded as an effective method to promote the separation of charge carriers in PNCs. However, the low interfacial quality and non-directional charge transfer in heterojunction lead to low charge transfer efficiency. Herein, a CsPbBr₃–CdZnS heterojunction is designed and prepared via an in situ hot-injection method for photocatalytic CO₂ reduction. It is found that the high-quality interface in heterojunction and anisotropic charge transfer of CdZnS nanorods (NRs) enable efficient spatial separation of charge carriers in CsPbBr₃–CdZnS heterojunction. The CsPbBr₃–CdZnS heterojunction achieves a higher CO yield (55.8 µmol g⁻¹ h⁻¹) than that of the pristine CsPbBr₃ NCs (13.9 µmol g⁻¹ h⁻¹). Furthermore, spectroscopic experiments and density functional theory (DFT) simulations further confirm that the suppressed recombination of charge carriers and lowered energy barrier for CO₂ reduction contribute to the improved photocatalytic activity of the CsPbBr₃–CdZnS heterojunction. This work demonstrates a valid method to construct high-quality heterojunction with directional charge transfer for photocatalytic CO₂ reduction. This study is expected to pave a new avenue to design perovskite–chalcogenide heterojunction.     

Porous Host–Guest MOF-Semiconductor Hybrid with Multisites Heterojunctions and Modulable Electronic Band for Selective Photocatalytic CO2 Conversion and H2 Evolution

Optimizing catalysts for competitive photocatalytic reactions demand individually tailored band structure as well as intertwined interactions of light absorption, reaction activity, mass, and charge transport.  Here, a nanoparticulate host–guest structure is rationally designed that can exclusively fulfil and ideally control the aforestated uncompromising requisites for catalytic reactions. The all-inclusive model catalyst consists of porous Co₃O₄ host and Zn_xCd_1-xS guest with controllable physicochemical properties enabled by self-assembled hybrid structure and continuously amenable band gap. The effective porous topology nanoassembly, both at the exterior and the interior pores of a porous metal–organic framework (MOF), maximizes spatially immobilized semiconductor nanoparticles toward high utilization of particulate heterojunctions for vital charge and reactant transfer. In conjunction, the zinc constituent band engineering is found to regulate the light/molecules absorption, band structure, and specific reaction intermediates energy to attain high photocatalytic CO₂ reduction selectivity. The optimal catalyst exhibits a H₂-generation rate up to 6720 µmol g⁻¹ h⁻¹ and a CO production rate of 19.3 µmol g⁻¹ h⁻¹. These findings provide insight into the design of discrete host–guest MOF-semiconductor hybrid system with readily modulated band structures and well-constructed heterojunctions for selective solar-to-chemical conversion.     

ZnO复合石墨相氮化碳纳米片的制备及其光催化性能研究

为了提高石墨相氮化碳光催化性能,本文以尿素、硫脲、醋酸锌为前驱体,通过氧化热剥离与共混煅烧法分别制备g-C₃N₄纳米片和ZnO/g-C₃N₄异质结复合材料,并采用TEM、FTIR、XRD、UV-Vis DRS、BET等表征手段对制备的催化剂进行结构表征。以罗丹明、大肠杆菌为探针,考察了催化剂的光催化降解性能和抑菌活性。结果表明：以尿素和硫脲为前驱体,经过氧化热剥离处理后能得到的g-C₃N₄ 2D纳米片,其比表面积更大、光催化性能更加优异,且其对罗丹明的降解率较未剥离的g-C₃N₄提高了21.2%。在40 min氙灯照射下,纯g-C₃N₄并未表现出良好的抑菌性能,而通过ZnO复合制备的ZnO/g-C₃N₄异质结复合材料,在光催化降解率和抑菌活性方面均有很大提高,其中复合20%ZnO制得的ZnO异质结复合材料表现出最佳的光催化性能...     

Facile synthesis of strontium molybdate coupled g-C3N4 composite for effective tetracycline and dyes degradation under visible light

This work was designed to synthesize SrMoO₄/g-C₃N₄ heterojunction for efficient degradation of tetracycline (TC) hydrochloride via photocatalysis. SrMoO₄/g-C₃N₄ samples were prepared through a grinding and roasting process. The prepared nanocomposite exhibited excellent visible-light-driven photocatalytic activity. The reaction rate of TC photodegradation reaches 0.0171 min^?1, which is 5.9 times higher than that of neat g-C₃N₄. The origin of the high photoactivity of SrMoO₄/g-C₃N₄ was investigated using a variety of characterization techniques including XRD, FT-IR, TG, SEM, TEM, XPS, DRS, Mott-Schottky, PL, PC, and EIS. Result showed that the added SrMoO₄ was closely loaded on the g-C₃N₄ surface, which is conducive to the electron transfer between SrMoO₄ and g-C₃N₄. Mott-Schottky analysis indicated that SrMoO₄ has a lower conduction band (CB) position than g-C₃N₄. As a result, photogenerated electrons in g-C₃N₄ can move to the CB of SrMoO₄ to hinder the recombination of charge carriers, thereby increasing the photocatalytic activity under visible light. The cycling test further suggested that the SrMoO₄/g-C₃N₄ heterojunction has good stability in the photocatalytic degradation of TC. Super oxygen radicals and holes are the main reactive species.     

Controlling the charge carriers recombination kinetics on the g-C3N4-BiSI n-n heterojunction with efficient photocatalytic activity in N2 fixation and degradation of MB and phenol

The challenges like the photocatalytic reduction of N₂ and elimination of contaminants from the wastewater are accessible by low cost, stable, and visible-light-driven semiconductor-based photocatalysis. A novel g-C₃N₄/BiSI nanocomposite was synthesized by hydrothermal method and applied for the first time in photocatalytic nitrogen fixation and degradation of methylene blue dye and phenol. The physicochemical features of the photocatalysts were studied by XRD, XPS, FTIR, BET, DRS, FESEM, TEM, EDX mapping, PL, EIS, Mott-Schottky, and photocurrent techniques. Experimental results showed that the production of ammonia in the presence of g-C₃N₄/BiSI nanocomposite was 1280 μmol L^?1 g^?1, while this values for g-C₃N₄ and BiSI were 274 μmol g^?1 L^?1 and 126 μmol g^?1 L^?1, respectively. Moreover prepared nanocomposite exhibited a higher rate constant in the MB (537.5 × 10^?4 min^?1) and phenol (353 × 10^?4 min^?1) degradation compared with the counterparts. The charge separation efficiency obviously improved, which was ascribed to the charges migration between g-C₃N₄ and BiSI in an n-n heterojunction system. In addition, high specific surface area and strong visible light absorption were identified as other factors affecting photocatalytic performance. This unique heterojunction photocatalyst has wide application prospects in environmental treatment.     

Tailoring Advanced N-Defective and S-Doped g-C3N4 for Photocatalytic H2 Evolution

Although challenges remain, synergistic adjusting various microstructures and photo/electrochemical parameters of graphitic carbon nitride (g-C₃N₄) in photocatalytic hydrogen evolution reaction (HER) are the keys to alleviating the energy crisis and environmental pollution. In this work, a novel nitrogen-defective and sulfur-doped g-C₃N₄ (S-g-C₃N₄-D) is designed elaborately. Subsequent physical and chemical characterization proved that the developed S-g-C₃N₄-D not only displays well-defined 2D lamellar morphology with a large porosity and a high specific surface area but also has an efficient light utilization and carriers-separation and transfer. Moreover, the calculated optimal Gibbs free energy of adsorbed hydrogen (ΔG_H*) for S-g-C₃N₄-D at the S active sites is close to zero (≈0.24 eV) on the basis of first-principle density functional theory (DFT). Accordingly, the developed S-g-C₃N₄-D catalyst shows a high H₂ evolution rate of 5651.5 µmol g⁻¹ h⁻¹. Both DFT calculations and experimental results reveal that a memorable defective g-C₃N₄/S-doped g-C₃N₄ step-scheme heterojunction is constructed between S-doped domains and N-defective domains in the structural configuration of S-g-C₃N₄-D. This work exhibits a significant guidance for the design and fabrication of high-efficiency photocatalysts.     

Electroreduction of Carbon Dioxide Driven by the Intrinsic Defects in the Carbon Plane of a Single Fe–N4 Site

Manipulating the in‐plane defects of metal–nitrogen–carbon catalysts to regulate the electroreduction reaction of CO₂ (CO₂RR) remains a challenging task. Here, it is demonstrated that the activity of the intrinsic carbon defects can be dramatically improved through coupling with single‐atom Fe–N₄ sites. The resulting catalyst delivers a maximum CO Faradaic efficiency of 90% and a CO partial current density of 33 mA cm^?2 in 0.1 m KHCO_3. The remarkable enhancements are maintained in concentrated electrolyte, endowing a rechargeable Zn–CO₂ battery with a high CO selectivity of 86.5% at 5 mA cm^?2. Further analysis suggests that the intrinsic defect is the active sites for CO₂RR, instead of the Fe–N₄ center. Density functional theory calculations reveal that the Fe–N₄ coupled intrinsic defect exhibits a reduced energy barrier for CO₂RR and suppresses the hydrogen evolution activity. The high intrinsic activity, coupled with fast electron‐transfer capability and abundant exposed active sites, induces excellent electrocatalytic performance.     

Preparation of visible light responsive g-C3N4/H-TiO2 Z-scheme heterojunction with enhanced photocatalytic activity for RhB degradation

The development of high-efficiency heterojunction with improved photocatalytic property is regarded as a promising way to decontaminate wastewater. In this study, Z-Scheme g-C₃N₄/H-TiO₂ heterojunctions with different proportions were synthesized. The photocatalytic degradation of rhodamine B (RhB) was studied under visible light irradiation. Among them, 10% g-C₃N₄/H-TiO₂ photocatalyst had the best performance, and the degradation rate of RhB was 65% within 120 min. In addition, 10% g-C₃N₄/H-TiO₂ photocatalyst had high stability, and its photocatalytic activity did not decrease significantly after four cycles. Through photocurrent analysis, it is found that the photogenerated carriers have obviously excellent separation and transfer characteristics, which makes the 10% g-C₃N₄/H-TiO₂ photocatalyst have good degradation performance. Electron paramagnetic resonance (ESR) experiments showed that ·OH and ·O₂^? were active radicals during degradation.

     

Facile preparation and enhanced photocatalytic H2-production activity of Cu(OH)2 nanospheres modified porous g-C3N4

A facile precipitation approach for the preparation of Cu(OH)₂/g-C₃N₄ composite photocatalysts with good porous structure was developed for the first time. The as-synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–visible light (UV–vis) absorbance spectra, photoluminescence (PL) and X-ray photoelectron spectroscopy (XPS). A photocatalytic water splitting reaction on the as-prepared photocatalysts were carried out under visible light irradiation. The results revealed that the prepared samples showed significantly enhanced photocatalytic activity. The optimal Cu(OH)₂ loading content was found to be 0.34 mol%, giving an H₂-production rate of 48.7 μmol h⁻¹ g⁻¹, which is higher 16.5 times than that of pure g-C₃N₄. This high photocatalytic H₂-production activity is attributed to the presence of Cu(OH)₂ clusters on the surface of the porous g-C₃N₄, which efficiently promotes the visible light absorption and separation of photogenerated electron–hole pairs.     

Highly efficient nanostructured metal-decorated hybrid semiconductors for solar conversion of CO2 with almost complete CO selectivity

Photocatalytic reduction of CO₂ into solar fuels is regarded as a promising method to address global warming and energy crisis problems. Although heterostructured hybrid metal oxide catalysts have been used for CO₂ reduction, selective control for CO production-only remains the subject of debate. In this paper, we report an absolute selectivity for CO production-only with enhanced photocatalytic ability using Ag-decorated reduced titanium oxide/tungsten hybrid nanoparticles (blue TiO₂/WO₃–Ag HNPs) at 1166.72 μmol g⁻¹ h⁻¹ with an apparent quantum yield of 34.8%. The construction of a Z-scheme between blue TiO₂ and WO₃ domains with an excellent band alignment provided remarkably improved separation of photoinduced charges. Importantly, the presence of novel Ag not only produces the highest selectivity up to 100% CO production-only, but also increases the photocatalytic electron reaction rate (2333.44 μmol g⁻¹ h⁻¹).     

Regulation of Electrocatalytic Behavior by Axial Oxygen Enhances the Catalytic Activity of CoN4 Sites for CO2 Reduction

Recent studies have found that the existence of oxygen around the active sites may be essential for efficient electrochemical CO₂-to-CO conversion. Hence, this work proposes the modulation of oxygen coordination and investigates the as-induced catalytic behavior in CO₂RR. It designs and synthesizes conjugated phthalocyanine frameworks catalysts (CPF-Co) with abundant CoN₄ centers as an active source, and subsequently modifies the electronic structure of CPF-Co by introducing graphene oxide (GO) with oxygen-rich functional groups. A systematic study reveals that the axial coordination between oxygen and the catalytic sites could form an optimized O-CoN₄ structure to break the electron distribution symmetry of Co, thus reducing the energy barrier to the activation of CO₂ to COOH*. Meanwhile, by adjusting the content of oxygen, the proper supports can also facilitate the charge transfer efficiency between the matrix layer and the catalytic sites. The optimized CPF-Co@LGO exhibits a high TOF value (2.81 s⁻¹), CO selectivity (97.6%) as well as stability (24 h) at 21 mA cm⁻² current density. This work reveals the modulation of oxygen during CO₂RR and provides a novel strategy for the design of efficient electrocatalysts, which may inspire new exploration and principles for CO₂RR.     

Promoting Electrocatalytic CO2 Reduction to CH4 by Copper Porphyrin with Donor–Acceptor Structures

Molecular catalysts have been receiving increasingly attention in the electrochemical CO₂ reduction reaction (CO₂RR) with attractive features such as precise catalytic sites and tunable ligands. However, the insufficient activity and low selectivity of deep reduction products restrain the utilization of molecular catalysts in CO₂RR. Herein, a donor–acceptor modified Cu porphyrin (CuTAPP) is developed, in which amino groups are linked to donate electrons toward the central CuN₄ site to enhance the CO₂RR activity. The CuTAPP catalyst exhibited an excellent CO₂-to-CH₄ electroreduction performance, including a high CH₄ partial current density of 290.5 mA cm⁻² and a corresponding Faradaic efficiency of 54.8% at –1.63 V versus reversible hydrogen electrode in flow cells. Density functional theory calculations indicated that CuTAPP presented a much lower energy gap in the pathway of producing *CHO than Cu porphyrin without amino group modification. This work suggests a useful strategy of introducing designed donor–acceptor structures into molecular catalysts for enhancing electrochemical CO₂ conversion toward deep reduction products.